Internal telephone system, information processing method, and relay device

Abstract

The SIP server efficiently identifies when a terminal device is out of range. [Solution] The extension system comprises a first terminal, a second terminal, a relay device, and a SIP server. The relay device includes a forwarding unit that forwards registration messages sent from the first terminal to the SIP server, and an out-of-range notification unit that communicates with the first terminal and, if it determines that the first terminal is out of range, notifies the SIP server of a deregistration message indicating that the first terminal is out of range. The SIP server includes a registration unit that, upon receiving a registration message, registers the management information contained in the registration message in the extension table, a deletion unit that, upon receiving a deregistration message, deletes the management information from the extension table, and a provision unit that, upon receiving an outgoing message from the second terminal to the first terminal, determines whether the first terminal is out of range based on the management information in the extension table, and if the first terminal is out of range, provides an out-of-range service to the second terminal.

Description

TECHNICAL FIELD

[0001] The present invention relates to an extension system and the like.

BACKGROUND ART

[0002] In a SIP (Session Initiation Protocol) telephone system, a smartphone installed with an extension application (application) (hereinafter referred to as a smartphone extension) is used as a telephone terminal for performing extension communication. The smartphone extension performs data communication with a SIP server via a Wi-Fi network to provide an extension telephone function, but may be out of service depending on the radio wave condition of the Wi-Fi network.

[0003] For example, upon receiving an incoming call, the SIP server transmits an incoming call signal to the smartphone extension of the called party, and upon receiving a response to the incoming call signal, establishes a call between the smartphone extension of the called party and the smartphone extension of the calling party.

[0004] On the other hand, if the SIP server does not receive a response to the incoming call signal before a timeout after transmitting the incoming call signal to the smartphone extension of the called party, the SIP server determines that the smartphone extension of the called party is out of service, and performs measures such as transmitting an out-of-service announcement or performing out-of-service transfer to the smartphone extension of the calling party.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0005]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, with the conventional technology described above, the SIP server could not efficiently identify that terminal devices such as smartphone extensions were out of range.

[0007] For example, after a SIP server sends an incoming call signal to the recipient's smartphone extension, it cannot determine whether the smartphone extension is out of range until a timeout occurs. As a result, it cannot quickly take action such as sending an out-of-range message to the caller's smartphone extension or forwarding the call to an out-of-range location.

[0008] In one aspect, the present invention aims to provide an extension system, an information processing method, and a relay device that enable a SIP server to efficiently identify when a terminal device is out of range. [Means for solving the problem]

[0009] In the first proposal, the extension system comprises a first terminal, a second terminal, a relay device, and a SIP (Session Initiation Protocol) server, and is an extension system that establishes an extension telephone between the first terminal and the second terminal. The relay device comprises a transfer unit that transfers a registration message sent from the first terminal to the SIP server, and an out-of-service notification unit that communicates with the first terminal and, if it determines that the first terminal is out of service, notifies the SIP server of a deregistration message indicating that the first terminal is out of service. The SIP server comprises a registration unit that, upon receiving the registration message, registers the management information contained in the registration message in the extension table, a deletion unit that, upon receiving the deregistration message, deletes the management information from the extension table, and a provision unit that, upon receiving an outgoing message from the second terminal to the first terminal, determines whether the first terminal is out of service based on the management information in the extension table, and if the first terminal is out of service, provides an out-of-service service to the second terminal. [Effects of the Invention]

[0010] The SIP server can efficiently determine that the terminal device is out of range. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows an example of a conventional system. [Figure 2] Figure 2 is a sequence diagram (1) showing the processing procedure of the conventional system. [Figure 3] Figure 3 is a sequence diagram (2) showing the processing procedure of the conventional system. [Figure 4] Figure 4 shows the system according to this embodiment. [Figure 5] Figure 5 is a sequence diagram (1) showing the processing procedure of the system according to this embodiment. [Figure 6] Figure 6 is a sequence diagram (2) showing the processing procedure of the system according to this embodiment. [Figure 7] Figure 7 is a functional block diagram showing the configuration of the AP according to this embodiment. [Figure 8] Figure 8 shows an example of the data structure of a management table. [Figure 9] Figure 9 is a functional block diagram showing the configuration of the SIP server according to this embodiment. [Figure 10] Figure 10 shows an example of the data structure of an extension table. [Figure 11] Figure 11 shows an example of a computer hardware configuration that achieves similar functionality to the AP in the embodiment. [Figure 12] Figure 12 shows an example of a computer hardware configuration that achieves similar functionality to the SIP server in the embodiment. [Modes for carrying out the invention]

[0012] The following describes in detail, with reference to the drawings, embodiments of the internal telephone system, information processing method, and relay device disclosed in this application. However, this embodiment does not limit the present invention. [Examples]

[0013] Before describing the system according to the present embodiment, an example of a conventional system will be described more specifically. Figure 1 is a diagram illustrating an example of a conventional system. As shown in Figure 1, the conventional system 5 includes smartphone extensions 10A and 10B, an AP (Access Point) 20, and a SIP server 30. For example, the smartphone extension 10A and the AP 20 are connected via a Wi-Fi network. The AP 20 and the SIP server 30 are connected via a network. The SIP server 30 and the smartphone extension 10B are connected via an AP (not shown) and a network.

[0014] The smartphone extensions 10A and 10B are smartphones or the like on which an extension application for performing extension communication is installed.

[0015] The AP 20 is a device that relays SIP communication performed between the smartphone extension 10A and the SIP server 30.

[0016] The SIP server 30 is a server that establishes a call between the originating-side smartphone extension (for example, the smartphone extension 10B) and the terminating-side smartphone extension (for example, the smartphone extension 10A).

[0017] For example, the smartphone extension 10A periodically transmits a registration message (Register) to the SIP server 30 via the AP 20. The registration message includes management information. The management information includes the MAC (Media Access Control) address of the smartphone extension 10A, the IP address of the smartphone extension 10A, and the extension number of the smartphone extension 10A.

[0018] The AP 20 forwards the registration message received from the smartphone extension 10A to the SIP server 30. When forwarding the registration message, the AP 20 registers the MAC address in the management information.

[0019] When SIP server 30 receives a registration message from smartphone extension 10A, it registers the management information and sets a registration acceptance time. If it does not receive another registration message from smartphone extension 10A within a specified time from the registration acceptance time, it deletes the management information for smartphone extension 10A.

[0020] The process for when smartphone extension 10B makes an internal call to smartphone extension 10A will be explained separately for cases where smartphone extension 10A is within range and cases where it is outside the range. Note that communication between smartphone extensions 10A and 10B and the SIP server 30 takes place via an AP (for example, AP20), but this will not be explained here.

[0021] First, when smartphone extension 10A is within range, the following process takes place. SIP server 30 receives an INVITE message from smartphone extension 10B to smartphone extension 10A, and if it has the management information for smartphone extension 10A, it forwards the INVITE message to smartphone extension 10A. Upon receiving the INVITE message, smartphone extension 10A sends a response message (200 OK) to SIP server 30. SIP server 30 then forwards the response message to smartphone extension 10B, thereby establishing a call between smartphone extension 10A and smartphone extension 10B.

[0022] On the other hand, if smartphone extension 10A is out of range, the following process is performed. The SIP server 30 forwards an INVITE message to smartphone extension 10A, then starts counting the call response waiting timer. If no response message is received from smartphone extension 10A after a predetermined time has elapsed, the SIP server 30 takes action such as sending an out-of-range message to smartphone extension 10B or forwarding the call to an out-of-range location.

[0023] Incidentally, AP20 periodically sends NULL data to smartphone extension 10A to recognize whether smartphone extension 10A is out of range or not. If AP20 receives a response from smartphone extension 10A within a predetermined time after sending the NULL data, it recognizes that smartphone extension 10A is within range. On the other hand, if AP20 does not receive a response from smartphone extension 10A within a predetermined time after sending the NULL data, it recognizes that smartphone extension 10A is out of range. If AP20 receives a message addressed to smartphone extension 10A from SIP server 30 while smartphone extension 10A is out of range, it discards that message.

[0024] Next, we will explain an example of the processing procedure of the conventional system 5. Figures 2 and 3 are sequence diagrams showing the processing procedure of the conventional system. In the example shown in Figures 2 and 3, we will explain assuming that smartphone extension 10A sends a registration message to SIP server 30 and then goes out of range for a while, and while smartphone extension 10A is out of range, smartphone extension 10B makes a call to smartphone extension A.

[0025] First, let's explain Figure 2. Smartphone extension 10A sends a registration message (Register) to AP20 addressed to SIP server 30 (step S10). For example, the registration message includes management information.

[0026] AP20 forwards the registration message to SIP server 30 and registers the MAC address included in the management information of the registration message (step S11). SIP server 30 receives the registration message and registers the IP address (MAC address) and extension number of the management information (step S12). SIP server 30 sets the registration acceptance time (step S13).

[0027] The SIP server 30 sends a registration OK message (200 OK) to the AP20, addressed to smartphone extension 10A (step S14). The AP20 forwards the registration OK message to smartphone extension 10A (step S15). Smartphone extension 10A receives the registration OK message (step S16).

[0028] Smartphone extension 10A sends a registration message (Register) to AP20 addressed to SIP server 30 (step S17). For example, the registration message contains management information. AP20 forwards the registration message to SIP server 30 (step S18). SIP server 30 receives the registration message and updates the registration acceptance time (step S19). Here, it is assumed that smartphone extension 10A is out of range or powered off after the processing in step S16.

[0029] AP20 sends NULL data to smartphone extension 10A (step S20). If AP20 does not receive a response from smartphone extension 10A, it recognizes that the smartphone extension is out of range (step S21).

[0030] Next, we will move on to the explanation of Figure 3. Smartphone extension 10B sends an INVITE message to SIP server 30 with the extension number of smartphone extension 10A set (step S21). SIP server 30 receives the INVITE message (step S22). Since the extension number of smartphone extension 10A is recorded in the management information, SIP server 30 forwards the INVITE message to smartphone extension 10A and starts counting the outgoing response waiting timer (step S23). AP20 receives the INVITE message and discards it (step S24).

[0031] If SIP server 30 does not receive a response message from smartphone extension 10A after a predetermined time has elapsed since starting the outgoing response waiting timer, it will take action such as sending an out-of-range message or transferring the call to an out-of-range location to smartphone extension 10B (step S25). SIP server 30 will delete the management information of smartphone extension 10A after a predetermined time has elapsed since the registration acceptance time (step S26).

[0032] As explained using Figures 1 to 3, in the conventional system 5, after the SIP server 30 sends an INVITE message to the recipient's smartphone extension, it cannot determine whether the smartphone extension 10A is out of range until a timeout occurs. Therefore, it cannot quickly take action such as sending an out-of-range message to smartphone extension 10B or transferring the call out of range. The conventional system 5 has now been explained in more detail.

[0033] Next, an example of a system according to this embodiment will be described. Figure 4 is a diagram showing the system according to this embodiment. As shown in Figure 4, the system 6 according to this embodiment has smartphone extensions 10A and 10B, AP50, and SIP server 100. For example, smartphone extension 10A and AP50 are connected via a Wi-Fi network. AP50 and SIP server 100 are connected via a network. The SIP server 100 and smartphone extension 10B are connected via AP (not shown) and the network.

[0034] System 6 is an example of an internal extension system. Smartphone extension 10A is an example of a first terminal. Smartphone extension 10B is an example of a second terminal. AP50 is an example of a relay device.

[0035] For example, when AP50, which relays data between smartphone extension 10A and SIP server 100, determines that smartphone extension 10A is out of range, it notifies SIP server 100 in advance that smartphone extension A is out of range. This allows SIP server 100 to quickly identify that smartphone extension 10A is out of range, thereby improving the convenience of using smartphone extensions. A more detailed explanation follows.

[0036] Smartphone extensions 10A and 10B are smartphones with an extension app installed for making internal calls. The explanation for smartphone extensions 10A and 10B is the same as the explanation for smartphone extensions 10A and 10B in Figures 1 and 2.

[0037] AP50 is a device that relays SIP communication between smartphone extension 10A and SIP server 100. For example, when AP50 receives a registration message from smartphone extension 10A, it forwards the registration message to SIP server 100. The registration message contains management information for smartphone extension 10A. This management information includes the MAC (Media Access Control) address, IP address, and extension number of smartphone extension 10A.

[0038] AP50 maintains the management table 54a. AP50 records the MAC address, IP address (IP address of smartphone extension 10A), and extension number included in the management information in the management table 54a. AP50 also records the IP address of the SIP server 100 set as the destination of the registered message in the management table 54a.

[0039] Here, AP50 periodically sends NULL data to smartphone extension 10A using the MAC address registered in management table 54a. If AP50 receives a response from smartphone extension 10A within a predetermined time after sending the NULL data, it recognizes that smartphone extension 10A is within range. On the other hand, if AP50 does not receive a response from smartphone extension 10A within a predetermined time after sending the NULL data, it recognizes that smartphone extension 10A is out of range.

[0040] If AP50 detects that smartphone extension 10A is out of range, it sends a deregistration message to SIP server 100. The deregistration message includes the extension number of smartphone extension 10A that is out of range and the IP address of smartphone extension 10A.

[0041] The SIP server 100 is a server that establishes a call between a calling smartphone extension (for example, smartphone extension 10B) and a receiving smartphone extension (for example, smartphone extension 10A). The SIP server 100 has an extension table 141.

[0042] When SIP server 100 receives a registration message from smartphone extension 10A via AP50, it records the MAC address, IP address, extension number, and registration reception time of smartphone extension 10A in extension table 141. The registration reception time is the time the registration message was received. If SIP server 100 does not receive another registration message from smartphone extension 10A within a predetermined time from the registration reception time, it deletes the information for smartphone extension 10A (IP address, extension number, registration reception time). If SIP server 100 receives another registration message from smartphone extension 10A within a predetermined time from the registration reception time, it sets a new registration reception time.

[0043] Here, if SIP server 100 receives a deregistration message from AP50, it deletes the information corresponding to the extension number and IP address of the deregistration message from extension table 141. For example, if the extension number and IP address of the deregistration message are those of smartphone extension 10A, SIP server 100 deletes the extension number, IP address, and registration time of smartphone extension 10A from extension table 141. This allows SIP server 100 to determine that smartphone extension 10A is out of range at the time it receives the deregistration message from AP50.

[0044] Next, we will explain the process when smartphone extension 10B makes an internal call to smartphone extension 10A, separately for cases where smartphone extension 10A is within range and when it is outside the range. Note that communication between smartphone extensions 10A and 10B and the SIP server 100 takes place via an AP (for example, AP50), but this will not be explained here.

[0045] First, when smartphone extension 10A is within range, the following process takes place: SIP server 100 receives an invitation message from smartphone extension 10B to smartphone extension 10A. If smartphone extension 10A is within range, its extension number exists in extension table 141, so SIP server 100 forwards the invitation message to smartphone extension 10A. Upon receiving the invitation message, smartphone extension 10A sends a response message (200 OK) to SIP server 100. SIP server 100 then forwards the response message to smartphone extension 10B, thereby establishing a call between smartphone extension 10A and smartphone extension 10B.

[0046] On the other hand, if smartphone extension 10A is out of range, the following process takes place. SIP server 100 receives an invitation message (INVITE message) from smartphone extension 10B to smartphone extension 10A. Since smartphone extension 10A is out of range and its extension number does not exist, SIP server 100 sends an out-of-range message to smartphone extension 10B or performs other actions such as out-of-range forwarding.

[0047] Next, an example of the processing procedure of System 6 according to this embodiment will be described. Figures 5 and 6 are sequence diagrams showing the processing procedure of the system according to this embodiment. In the example shown in Figures 5 and 6, we will explain assuming that smartphone extension 10A goes out of range after sending a registration message to SIP server 30 for a while, and that while smartphone extension 10A is out of range, smartphone extension 10B makes a call to smartphone extension A.

[0048] First, let's explain Figure 5. Smartphone extension 10A sends a registration message (Register) to AP50 addressed to SIP server 30 (step S30). For example, the registration message includes management information.

[0049] AP50 forwards the registration message to SIP server 100 and registers information about the registration message in management table 54a (step S31). For example, in step S31, AP50 registers the MAC address of smartphone extension 10A, the IP address of smartphone extension 10A, the extension number of smartphone extension 10A, and the IP address of SIP server 100 in management table 54a (step S32). SIP server 100 sets the registration acceptance time (step S33).

[0050] The SIP server 100 sends a registration OK message (200 OK) to the AP 50, addressed to smartphone extension 10A (step S34). The AP 50 forwards the registration OK message to smartphone extension 10A (step S35). Smartphone extension 10A receives the registration OK message (step S36). Here, it is assumed that smartphone extension 10A is out of range or powered off after the processing in step S36.

[0051] AP50 sends NULL data to smartphone extension 10A (step S37). If AP50 does not receive a response from smartphone extension 10A, it recognizes that smartphone extension 10A is out of range (step S38).

[0052] AP50 sends an unregistration message (step S39). For example, the registration message will contain the extension number of smartphone extension 10A and the IP address of smartphone extension 10A. SIP server 100 receives the unregistration message (step S40) and proceeds to step S41 in Figure 6.

[0053] We will now proceed to the explanation of Figure 6. The SIP server 100 removes the IP address, extension number, and registration acceptance time of smartphone extension 10A from the extension table 141 (step S41). Smartphone extension 10B sends an INVITE message to the SIP server 100 with the extension number of smartphone extension 10A set (step S42).

[0054] The SIP server 100 receives the INVITE message (step S43). Since the extension number of smartphone extension 10A is not registered in the extension table 141, the SIP server 100 takes action such as sending an out-of-service message or transferring the call to an out-of-service area for smartphone extension 10B (step S44).

[0055] As explained in Figures 4 to 6, in the system 6 of this embodiment 1, when AP 50 recognizes that smartphone extension 10A is out of range, AP 50 sends a deregistration message to SIP server 100, and SIP server 100 deletes the extension number, etc., of smartphone extension 10A from extension table 141. In this way, AP 50 can efficiently notify SIP server 100 that smartphone extension 10A is out of range. Furthermore, when the receiving smartphone extension 10A is out of range, SIP server 100 can quickly respond to the INVITE message from the calling smartphone extension 10B by sending an out-of-range message or out-of-range forwarding.

[0056] Next, we will explain the configuration example of AP50 and the SIP server 100 as described in Figure 4. First, we will explain the configuration example of AP50. Figure 7 is a functional block diagram showing the configuration of the AP according to this embodiment. As shown in Figure 7, AP50 has a communication unit 51, an input unit 52, a display unit 53, a storage unit 54, and a control unit 55.

[0057] The communication unit 51 performs data communication with the smartphone extension 10A via the Wi-Fi network. This description explains the case where the communication unit 51 performs data communication with the smartphone extension 10A, but it may also perform data communication with other smartphone extensions. The communication unit 51 also performs data communication with the SIP server 100 via the network.

[0058] The input unit 52 is an input device for inputting various types of information to the control unit 55 of the AP50.

[0059] The display unit 53 is a display device that displays information output from the control unit 55.

[0060] The storage unit 54 has a management table 54a. The storage unit 54 is a memory or the like.

[0061] Management table 54a holds various data related to registered messages received from smartphone extension 10A. Figure 8 shows an example of the data structure of the management table. As shown in Figure 8, this management table 54a has item number, MAC address, IP address (smartphone extension), extension number, and IP address (SIP server).

[0062] The item number is a number that identifies the record in management table 54a. The MAC address is the MAC address included in the management information of the registered message. The IP address (smartphone extension) is the IP address included in the management information of the registered message. The extension number is the extension number included in the management information of the registered message. The IP address (SIP server) is the IP address of the SIP server set as the destination of the registered message.

[0063] The control unit 55 includes a transfer unit 55a and an out-of-range notification unit 55b. The control unit 55 is a CPU (Central Processing Unit), etc. Although not shown in the diagram, the control unit 55 acquires time information from an external server, timer, etc.

[0064] When the forwarding unit 55a receives a registration message from the smartphone extension 10A, it forwards the registration message to the SIP server 100. The forwarding unit 55a updates the management table 54a based on the information in the registration message. For example, the forwarding unit 55a registers the MAC address, IP address (smartphone extension), and extension number included in the management information of the registration message in the management table 54a. It also registers the destination address of the registration message as an IP address (SIP server) in the management table 54a.

[0065] If the forwarding unit 55a finds that the same information as the set of MAC address, IP address (smartphone extension), extension number, and IP address (SIP server) is already registered in the management table 54a, it skips the registration process for such information.

[0066] Furthermore, when the forwarding unit 55a receives a registration message (200 OK) or an INVITE message from the SIP server 100 addressed to the smartphone extension 10A, it forwards each message to the smartphone extension 10A. When the forwarding unit 55a receives a response message for an INVITE message from the smartphone extension 10A, it forwards the response message to the SIP server 100.

[0067] The out-of-range notification unit 55b determines whether the smartphone extension 10A is out of range by periodically sending NULL data to the smartphone extension 10A. For example, the out-of-range notification unit 55b sends NULL data every 60 seconds.

[0068] For example, the out-of-range notification unit 55b sets the MAC address of the smartphone extension 10A registered in the management table 54a as the destination for NULL data and sends NULL data to the smartphone extension 10A. If the out-of-range notification unit 55b does not receive a response within a predetermined time after sending NULL data to the smartphone extension 10A, it determines that the smartphone extension 10A is out of range.

[0069] If the out-of-range notification unit 55b determines that the smartphone extension 10A is out of range, it registers the extension number and IP address (smartphone extension) of the smartphone extension 10A in a deregistration message and notifies the SIP server 100 of the deregistration message. For example, the out-of-range notification unit 55b sets the IP address (SIP server) in the management table 54a as the destination for the deregistration message.

[0070] After notifying the SIP server 100 of the unregistered message, the out-of-range notification unit 55b deletes the record corresponding to the smartphone extension 10A (MAC address, IP address (smartphone extension), extension number, IP address (SIP server)) from the management table 54a.

[0071] Next, an example of the configuration of the SIP server 100 will be described. Figure 9 is a functional block diagram showing the configuration of the SIP server according to this embodiment. As shown in Figure 9, the SIP server 100 has a communication unit 110, an input unit 120, a display unit 130, a storage unit 140, and a control unit 150.

[0072] The communication unit 110 performs data communication with smartphone extensions (for example, smartphone extensions 10A and 10B) via the AP (AP50).

[0073] The input unit 120 is an input device for inputting various types of information to the control unit 150 of the SIP server 100.

[0074] The display unit 130 is a display device that displays information output from the control unit 150.

[0075] The storage unit 140 has an extension table 141. The storage unit 140 is a memory, etc.

[0076] The extension table 141 is used when establishing an extension phone line for each smartphone extension. Figure 10 shows an example of the data structure of the extension table. As shown in Figure 10, the extension table 141 contains item number, IP address (smartphone extension), extension number, and registration acceptance time.

[0077] The item number is a number that identifies the record in extension table 141. The IP address (smartphone extension) is the IP address included in the management information of the registered message. The extension number is the extension number included in the management information of the registered message. The registration acceptance time is the time the registration message was received.

[0078] The control unit 150 includes a registration unit 151, a deletion unit 152, and a provision unit 153. The control unit 150 is a CPU, etc. Although not shown in the figures, the control unit 150 acquires time information from an external server, timer, etc.

[0079] When the registration unit 151 receives a registration message from the smartphone extension 10A via AP50, it updates the extension table 141 based on the information in the registration message.

[0080] For example, the registration unit 151 registers the IP address and extension number of the management information contained in the registration message as the IP address (smartphone extension) and extension number in the extension table 141. In addition, the registration unit 151 registers the time the registration message was received as the registration acceptance time in the extension table 141.

[0081] The registration unit 151 updates the registration acceptance time if the IP address and extension number of the management information included in the registration message are already registered in the extension table 141.

[0082] Furthermore, when the registration unit 151 receives a registration message from smartphone extension 10A via AP50, it sends the registration message (200OK) to smartphone extension 10A.

[0083] When the deletion unit 152 receives a deregistration message from AP50, it deletes the corresponding record from the extension table 141. For example, when the deletion unit 152 receives a deregistration message with the IP address (smartphone extension) "aa.aa.aa.aa" and extension number "bbbb", it deletes the record corresponding to item "1" in the extension table 141 shown in Figure 10.

[0084] Furthermore, the deletion unit 152 deletes records from the extension table 141 that have elapsed a predetermined time since the registration acceptance time. For example, if a predetermined time has elapsed since the registration acceptance time "T1:T2:T3", the deletion unit 152 deletes the record with item number "1" in the extension table 141 shown in Figure 10.

[0085] When the service provider 153 receives an INVITE message from smartphone extension 10B to smartphone extension 10A, it determines whether smartphone extension 10A is out of range based on the extension table 141. For example, the INVITE message to smartphone extension 10A includes the extension number of smartphone extension 10A.

[0086] For example, if the extension number of smartphone extension 10A is not registered in the extension table 141, the service provider 153 determines that smartphone extension 10A is out of range. If the service provider 153 determines that smartphone extension 10A is out of range, it sends an out-of-range message to smartphone extension 10B. Alternatively, if the service provider 153 determines that smartphone extension 10A is out of range, it performs an out-of-range transfer operation for smartphone extension 10B. For example, the service provider 153 establishes a call between smartphone extension 10A and smartphone extension B using the external telephone number previously designated by the user of smartphone extension 10A. Note that the service provider 153 may use any prior art to perform the out-of-range transfer operation.

[0087] On the other hand, if the extension number of smartphone extension 10A is registered in the extension table 141, the service provider 153 determines that smartphone extension 10A is within range. In this case, the service provider 153 establishes an extension call by forwarding an INVITE message to smartphone extension 10A and then forwarding a response message from smartphone extension 10A to smartphone extension 10B, in the same manner as in conventional technology.

[0088] The above describes an example configuration of AP50 and SIP server 100.

[0089] Next, the effects of System 6 according to this embodiment will be explained. In System 6, when AP50, which relays data between smartphone extension 10A and SIP server 100, determines that smartphone extension 10A is out of range, it notifies SIP server 100 in advance that smartphone extension A is out of range. As a result, SIP server 100 can quickly identify that smartphone extension 10A is out of range, thereby improving the convenience of using smartphone extensions.

[0090] For example, AP50 periodically sends NULL data to smartphone extension 10A via the Wi-Fi network and determines whether smartphone extension 10A is out of range based on whether or not it receives a response. If AP50 determines that smartphone extension 10A is out of range, it sends a deregistration message to SIP server 100 to notify it that smartphone extension 10A is out of range. This allows SIP server 100 to quickly identify that smartphone extension 10A is out of range, thereby improving the convenience of using smartphone extensions.

[0091] Although embodiments applying the invention made by the present inventors have been described above, the present invention is not limited by the descriptions and drawings that constitute part of the disclosure of the present invention in these embodiments. That is, all other embodiments, examples, and operational techniques made by those skilled in the art based on these embodiments are included in the scope of the present invention.

[0092] Furthermore, in the above embodiment, the SIP server 100 registered the IP address and extension number of the smartphone extension in the extension table 141. However, when determining whether or not the smartphone extension is out of range, it is not always necessary to register the IP address and extension number. For example, the SIP server 100 may register the extension number in the extension table 141 and then determine whether or not the smartphone extension is out of range.

[0093] Next, an example of a computer hardware configuration that achieves the same functions as AP50 described above will be explained. Figure 11 is a diagram showing an example of a computer hardware configuration that achieves the same functions as AP in the embodiment. As shown in Figure 11, the computer 200 has a CPU 201 that performs various calculations, an input device 202 that receives data input from the user, and a display 203. The computer 200 also has a communication device 204 that exchanges data with smartphone extensions, SIP server 100, etc. via a wired or wireless network, and an interface device 205. The computer 200 also has a RAM 206 that temporarily stores various information and a hard disk drive 207. Each of the devices 201 to 207 is connected to a bus 208.

[0094] The hard disk drive 207 has a transfer program 207a and an out-of-range notification program 207b. The CPU 201 reads the transfer program 207a and the out-of-range notification program 207b and loads them into the RAM 206.

[0095] The transfer program 207a functions as the transfer process 206a. The out-of-range notification program 207b functions as the out-of-range notification process 206b.

[0096] The processing of the transfer process 206a corresponds to the processing of the transfer unit 55a. The processing of the out-of-range notification process 206b corresponds to the processing of the out-of-range notification unit 55b.

[0097] Furthermore, the transfer program 207a and the out-of-range notification program 207b do not necessarily have to be stored on the hard disk drive 207 from the beginning. For example, each program can be stored on a "portable physical medium" such as a flexible disk (FD), CD-ROM, DVD, magneto-optical disk, or IC card inserted into the computer 200. Then, the computer 200 can read and execute the transfer program 207a and the out-of-range notification program 207b.

[0098] Next, an example of a computer hardware configuration that implements the same functions as the SIP server 100 described above will be explained. Figure 12 shows an example of a computer hardware configuration that implements the same functions as the SIP server in the embodiment. As shown in Figure 12, the computer 300 has a CPU 301 that performs various calculations, an input device 302 that receives data input from the user, and a display 303. The computer 300 also has a communication device 304 that exchanges data with AP50 etc. via a wired or wireless network, and an interface device 305. The computer 300 also has a RAM 306 that temporarily stores various information and a hard disk drive 307. Each of the devices 301 to 307 is connected to a bus 308.

[0099] The hard disk drive 307 has a registration program 307a, a deletion program 307b, and a provision program 307c. The CPU 301 reads each of the programs 307a to 307c and loads them into the RAM 306.

[0100] The registration program 307a functions as the registration process 306a. The deletion program 307b functions as the deletion process 306b. The provision program 307c functions as the provision process 306c.

[0101] The processing in registration process 306a corresponds to the processing in registration unit 151. The processing in deletion process 306b corresponds to the processing in deletion unit 152. The processing in provision process 306c corresponds to the processing in provision unit 153.

[0102] Furthermore, programs 307a to 307c do not necessarily have to be stored on the hard disk drive 207 from the beginning. For example, each program could be stored on a "portable physical medium" such as a flexible disk (FD), CD-ROM, DVD, magneto-optical disk, or IC card inserted into the computer 300. Then, the computer 300 could read and execute each program 307a to 307c. [Explanation of Symbols]

[0103] 10A, 10B Smartphone extension 50 AP 51,110 Communications Department 52,120 Input section 53,130 Display section 54,140 storage section 54a Management Table 55,150 Control Unit 55a Transfer section 55b Out-of-range notification section 100 SIP servers 141 Extension Table 151 Registration Department 152 Deleted section 153 Provision Department

Claims

1. An extension system comprising a first terminal, a second terminal, a relay device, and a SIP (Session Initiation Protocol) server, for establishing an extension telephone between the first terminal and the second terminal, The relay device is, A transfer unit that transfers the registration message sent from the first terminal to the SIP server, The system includes an out-of-range notification unit that, upon performing communication with the first terminal and determining that the first terminal is out of range, notifies the SIP server of a deregistration message indicating that the first terminal is out of range. The SIP server mentioned above is When the aforementioned registration message is received, the registration unit registers the management information contained in the registration message into the extension table. When the aforementioned unregistration message is received, a deletion unit deletes the management information from the extension table. When a message is received from the second terminal to the first terminal, the system determines whether the first terminal is out of range based on the management information in the extension table, and if the first terminal is out of range, the system provides an out-of-range service to the second terminal. An internal telephone system characterized by having the following features.

2. The management information included in the registration message sent from the first terminal includes the address and extension number of the first terminal. The extension system according to claim 1, further characterized in that the transfer unit performs a process of registering the address of the first terminal, the extension number, and the address of the SIP server set as the destination of the registered message in a management table.

3. The extension system according to claim 2, characterized in that the providing unit determines that the first terminal is out of range when the extension number set in the outgoing message is not registered in the extension table.

4. The extension system according to claim 2 or 3, characterized in that the providing unit transmits an out-of-range message or transfers an out-of-range message to the second terminal when the first terminal is out of range.

5. An information processing method performed by an extension system that has a first terminal, a second terminal, a relay device, and a SIP (Session Initiation Protocol) server, and establishes an extension telephone between the first terminal and the second terminal, The relay device forwards the registration message sent from the first terminal to the SIP server. The relay device communicates with the first terminal and, if it determines that the first terminal is out of range, notifies the SIP server of a deregistration message indicating that the first terminal is out of range. When the SIP server receives the registration message, it registers the management information contained in the registration message in the extension table. When the aforementioned unregistration message is received, the management information is deleted from the extension table. When the second terminal receives an outgoing message from the first terminal, it determines whether the first terminal is out of range based on the management information in the extension table, and if the first terminal is out of range, it provides the second terminal with an out-of-range service. An information processing method characterized by performing a process.

6. A transfer unit that transfers registration messages sent from a terminal providing extension telephone functionality using a SIP (Session Initiation Protocol) server to the SIP server, A remote-of-service notification unit that communicates with the terminal and, if it determines that the terminal is out of range, notifies the SIP server of a deregistration message indicating that the terminal is out of range. A relay device characterized by having the following features.

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